Coastal flooding documented

A full moon and Hurricane Sandy spelled near-record flooding in Lewes, Del., last week, as documented in a time-lapse video by Delaware Sea Grant (DESG). The video shows tidal waters and Sandy-driven storm surge cover—and retreat from—East Savannah Road over three days.

"The storm tide is the sum of the predicted tide and the storm surge," said Wendy Carey, coastal processes specialist with Delaware Sea Grant. "It's the combined effects of the two."

Carey and Christopher Petrone, DESG education specialist, obtained permission from the city of Lewes to attach a time-lapse camera to a post, capturing one image every minute during daylight hours. The spot selected on Savannah Road is prone to flooding, but extreme conditions this week resulted in widespread inundation, which was seen throughout the state.

"One of the major threats from a coastal storm is flooding," Carey said. "People need to heed evacuation orders issued by their local emergency management officials. There are significant impacts from flooding not only for evacuation routes, but to properties too."

Delaware Sea Grant prepared a similar video last year during a Perigean spring tide when a northeaster tracked along the coast. Last year's storm tide measured at 7.55 feet, lower than the 8.70 foot storm tide associated with Sandy.

Petrone said he plans to set up an educational website to house the videos along with materials explaining the various astronomical and meterological factors at play.

"Our hope is to educate people on storm tides," Petrone said. "We all see water coming in, but most don't necessarily know why it's happening or how long it's going to last. Hopefully our educational resources will help folks understand the science."